Solid propellants of the aforementioned type generally have a low burning speed and a high pressure exponent. The burning speed or rate can be increased by adding solid, high-energy substances such as octogen (HMX) or hexogen (RDX), or metals having a high heat of combustion, such as aluminium or boron. Combinations with energy-rich binders serve the same function. These include isocyanate-bound glycidylazido polymers (GAP), nitrate ester-containing polymers, such as polyglycidyl nitrate and polynitratomethylethyloxetan or nitro-amino-substituted polymers. Even though this leads to a rise in the burning rate, the pressure exponent and the temperature coefficient are only slightly or not reduced.
Additions of ammonium perchlorate, which lead to a rise in the burning speed, admittedly reduce with a higher dosage the pressure exponent, but lead to the formation of hydrochloric acid in the exhaust and therefore to higher smoke formation with high atmospheric humidity.
In the case of double base and composite double base solid propellants the burning behaviour can be favourably influenced by adding lead and copper salts or oxides in conjunction with carbon black, but said additives can only be used to a limited extent in the case of ammonium nitrate-containing propellants. Said salts and oxides mainly act in the sense of increasing the burning rate, but do not allow an adequate drop of the pressure exponent.
The problem of the invention is to improve the burning behaviour of solid propellants based on pure and phase-stabilized ammonium nitrate.